1. Field of the Invention
The present invention relates to a zoom lens having a high variable magnification ratio used in electronic cameras such as digital cameras, video cameras, broadcasting cameras, surveillance cameras and the like, to a zoom lens having a camera shake correction function, and to an imaging apparatus including the zoom lens.
2. Description of the Related Art
Conventionally, a zoom lens substantially consisting of: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; a fourth lens group having positive refractive power; and a fifth lens group having negative refractive power, which are arranged in this order from the object side, is known as a zoom lens having relatively a high variable magnification ratio. The zoom lens with such a lens construction is known to be appropriate for realizing both a high variable magnification ratio and a reduction in size (see Japanese Unexamined Patent Publication No. 4 (1992)-070707, U.S. Pat. No. 5,872,659, and Japanese Unexamined Patent Publication No. 11 (1999)-064728)
As a zoom lens having “a camera shake correction function (a vibration-proof function)” for preventing image blurring attributed to vibration, camera shake and the like, a zoom lens that substantially consists of a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, and a fourth lens group having positive refractive power, arranged in this order from the object side, the third lens group of which comprises two groups, a partial group having positive refractive power and a partial group having negative refractive power, and that exhibits camera shake correction effects by moving the partial group having negative refractive power in a direction perpendicular to an optical axis, is known (see U.S. Pat. No. 6,462,885).